The invention relates to hearing aids, and more particularly relates to programmable hearing aids. In its most immediate sense, the invention relates to apparatus used to make an electrical connection between a programmable hearing aid and the programming unit used to program it.
A programmable hearing aid is a hearing aid in which certain characteristics of the aid (e.g. frequency response, attack and release times, AGC etc.) are adjustable by the hearing aid dispenser. Conventionally, such aids are programmed in situ, i.e. while they are in the patient's ear. This permits the patient and dispenser to check on the programming of the aid and to adjust the programming if the performance of the aid is substandard. In some classes of programmable hearing aids, the aid is programmed by plugging a male portion of a connector into a corresponding female portion that is mounted to the faceplate of the hearing aid.
Such a connector is highly undesirable when used on small hearing aids such as CIC (completely-in-canal) aids. This is because CIC aids vary in size and shape; the housing of each CIC aid is custom molded to the shape of the patient's ear. With such variations in size and shape, there is no guarantee that the faceplate will have room for the connector or that the other faceplate-mounted components can be appropriately located on the faceplate if the connector is provided. By way of example, the faceplate of a hearing aid must provide room for a microphone port, a vent opening, a battery door and a retrieval line. Furthermore, the location of these elements is not a mere matter of choice: the microphone port should be located as far as possible from the vent opening to prevent feedback, and the battery door must be so located that it can be opened and closed.
Furthermore, the female connector is difficult to install and to use. The female connector is difficult to install because it must be properly oriented with respect to the faceplate. This in turn comes about because the mating male connector often has a 45 degree bend. If the female connector is not properly oriented with respect to the faceplate, the male connector will, during use, press against the interior of the user's ear. It is likewise difficult to use the female connector, because the male connector must be properly aligned for a connection to be established and the small sizes of the connectors makes it difficult to see whether the alignment between them is in fact proper. If the alignment is incorrect, it is relatively easy to damage the male connector, the female connector or both while trying to make an electrical connection between them.
Additionally, because the location of the female connector cannot be predicted in advance of the manufacturing process, production personnel must be capable of deciding e.g. a) whether there is enough room for the female connector on the faceplate, b) where the female connector should be located with respect to the other components that must be mounted on the faceplate, and c) the best way to wire the connector to the circuitry inside the aid. It is consequently necessary to employ highly skilled individuals to assemble the aid.
U.S. Pat. No. 4,961,230 relates to a programming system whereby the electrical connections necessary to program the aid are accessed through the door of the aid, thereby eliminating the need for a faceplate-mounted female connector. In this system, the dispenser removes the battery from the aid and inserts a programming “pill” that fits in the battery compartment. The dispenser then closes the door, places the aid in the user's ear, and programs the aid in situ.
While this system does away with the need for a female connector on the faceplate of the aid, it introduces disadvantages of its own. One such disadvantage is caused by the requirement that the cable connecting the programming pill with the programming unit be relatively thick.
In the system disclosed in U.S. Pat. No. 4,961,230 the battery is removed during the programming operation and power must be supplied through the cable. For this reason, and because modern hearing aids have many programmable functions, a cable for programming a modern CIC aid must contain four electrical conductors and the cable must be shielded against noise. Additionally, the cable must be mechanically robust to have the necessary durability, and for this reason also the cable must have a certain thickness. Because the cable is required to be relatively thick and because the cable must be able to exit the battery compartment with the battery door closed, the battery door cannot fit closely to the faceplate; sufficient clearance must exist so the cable can get out.
A loosely-fitting battery door is not only aesthetically unsatisfactory, but also seriously degrades the performance of the aid. This is because the opening between the door and the faceplate establishes an acoustic coupling with the microphone. This causes feedback.
This known system has other disadvantages as well. Because the programming pill and the cable are relatively bulky, they change the aural characteristics of the patient's outer ear. As a result, the patient's unaided hearing during programming of the aid is different from the patient's unaided hearing when the programming apparatus has been removed from the patient's ear. Furthermore, the power supply from the programming unit has different electrical characteristics from those of an installed battery, and the aid functions differently when powered by the programming unit.
U.S. Pat. No. 5,799,095 (herein incorporated by reference) discloses a beside-the-door programming system for programming hearing aids that purports to address the above problems. However, the ′095 patent does not completely solve these problems. Because the terminals that receive the female connector are on a printed circuit board 54 within the hearing aid housing at a significant distance from the faceplate 22, there is a large arm of movement between the pivot point of the collar 66 where it abuts against the faceplate 22 and the board 54. Any slight movement of the cable 64 during programming of the hearing aid can cause the electrodes 58-63 to come loose from the circuit board 54, thus breaking the connection.
U.S. Pat. No. 6,678,386 discloses a programmable module 300 that fits into a slot 220 in the battery door opening of the hearing aid. However, because of the bulk of the module, caused by the necessity for spring connectors and fingers, and the necessity for an additional wall, the slot 220 must be made much larger than that disclosed in the ′095 patent. This in turn impacts the manufacturing process and the placement of the battery door opening on the faceplate. Furthermore, the battery door must be more loosely fitting, with the disadvantages of such loose fit discussed above.
There is a need for a new hearing aid programming system that addresses the above problems.